---
id: 6578b13757611e2825beb8a5
title: Passo 3
challengeType: 20
dashedName: step-3
---

# --description--

Keys must be unique within a dictionary and they can be only immutable data types. This means you cannot use a list or another dictionary as keys.

Add another key `age` to your dictionary and give it the integer number `2` as value.

# --hints--

You should add a new key-value pair to your `copper` dictionary.

```js
({ test: () => assert(__pyodide.runPython(`
    copper = __locals.get("copper")
    len(copper) == 2
  `))
})
```

You should have an `age` key with the value `2` just after `'species': 'guinea pig'`, inside your `copper` dictionary. Don't forget the comma.

```js
({ test: () => assert(__pyodide.runPython(`
    copper = __locals.get("copper")
    copper == {"species": "guinea pig", "age": 2}
  `))
})
```

# --seed--

## --seed-contents--

```py
--fcc-editable-region--
copper = {'species': 'guinea pig'}
--fcc-editable-region--
```
